Baby sleep requirements:

A guide for the science-minded

© 2008 -2014, Gwen Dewar, Ph.D., all rights reserved

If you look up baby sleep requirements in a modern parenting book, you might find a table like this:

Total sleep time required over a 24-hour period

• Newborn.......16-17 hours

• 1-6 months....15-16 hours

• 6-12 months...14 hours

• 1-2 years.....13-14 hours

The tables seem authoritative and concise. But what are they based on?

The authors almost never cite their sources, and I suspect it’s because they don’t have any.

Why?

Because even the best advice involves guesswork.

These guesses may be good enough for some purposes. But if you’re having sleep problems, or your baby's sleep patterns seem unusual, it's helpful to delve deeper. By reviewing the scientific evidence for baby sleep requirements, you can do a better job of judging your baby’s personalized needs.

Here I explain how scientists estimate sleep requirements for the average baby, and I report the results of one of the most extensive studies of average sleep duration in babies.

This information--combined with tips on how to tell if your baby is overtired--will help you determine how much sleep your baby needs.

In addition, if your baby is very young, check out this article about newborn baby sleep requirements and patterns.  If your child is older than two years, see my article about the sleep needs of toddlers and big kids. And for information about how babies fall asleep--and how you can help your baby stay asleep--see this article about the biology of baby sleep.

How baby sleep requirements are estimated

Everybody knows that babies need more sleep than older children do. But how much?

When I began researching baby sleep requirements, I assumed that those authoritative charts we see published everywhere—the ones telling us that the average newborn needs 16 hours of sleep, for example—were based on scientifically-established, biological needs.

I figured that somebody must have identified a link between, say, a certain minimum number of sleep hours and optimal rates of childhood growth. Or between sleep hours and rates of infection.

I was wrong.

It turns out that scientists know relatively little about baby sleep requirements. The sleep charts that you see in parenting books and websites are based on how much time parents—typically, Western parents—say their babies spend sleeping.

For instance, studies of Australian babies reveal that the average newborn gets about 16-17 hours of sleep over a 24-hour period. Babies aged 4-6 months average 14 hours (So et al 2007; Price et al 2014).

Do such average sleep times predict your baby’s sleep requirements?

Maybe. It seems plausible that most infants are pretty good self-regulators of their own sleep needs. Give your baby enough opportunities, and he may naturally meet his own baby sleep requirements. If that’s true—and if most parents give their babies the necessary opportunities—then studies of real-world sleep behavior may tell us a lot about baby sleep requirements.

But it’s a bit more complicated than that.

For one thing, different individuals have different needs. This may be especially true for baby sleep requirements. As the data below show, babies vary tremendously in the number of hours that they sleep.

Another important point is that sleep habits vary from culture to culture. Children in living in different nations get different amounts of sleep, and average sleep times have changed from generation to generation.

Based on a recent telephone survey conducted by the National Sleep Foundation, American kids—including babies—seem to be sleeping less than they used to (National Sleep Foundation 2004).

A similar trend towards less sleep has been documented in Switzerland, (Iglowstein et al 2003), Saudi Arabia (Bahamman et al 2006), Hong Kong (Ng 2005), Australia (Smedje 2007), Israel, and Finland (Tynjala et al 1993).

Are contemporary kids in these countries getting the right amount of sleep? Some researchers suspect not. But until more research has been done, nobody knows for sure.

So sleep charts are not necessarily the last word on baby sleep requirements. To estimate your baby’s own, individualized needs, you need to supplement information from sleep charts with your own observations of your baby’s behavior.

Below I provide detailed data from one of the best modern studies of average sleep times (Iglowstein et al 2003). As you check the numbers out, be sure to notice how widely sleep times vary for each age group.

Baby sleep requirements: Evidence from a longitudinal study 

Iglowstein and colleagues tracked 493 Swiss children from birth to 16 years (Iglowstein et al 2003). Here are the sleep patterns they observed for children under the age of 2 years. They may serve as a rough guide to baby sleep requirements.

1 month old:

• The average baby got a total of 14-15 hours of sleep

• 50% of babies got between 13 and 16 hours

• 96% of babies got between 9 and 19 hours


3 months old:

• The average baby got a total of 14-15 hours of sleep

• 50% of babies got between 13 and 16 hours

• 96% of babies got between 10 and 19 hours


6 months old:

• the average baby got about 14.2 hours of total sleep

• 50% of babies got between 13 and 15.5 hours

• 96% of babies got between 10.4 and 18.1 hours


9 months old:

• the average baby got about 13.9 hours of total sleep

• 50% of babies got between 12.8 and 15 hours

• 96% of babies got between 10.5 and 17.4 hours


1 year old:

• the average baby got about 13.9 hours of total sleep

• 50% of babies got between 13 and 14.8 hours

• 96% of babies got between 11.4 and 16.5 hours


18 months old:

• the average baby got about 13.6 hours of total sleep

• 50% of babies got between 12.7 and 14.5 hours

• 96% of babies got between 11.1 and 16 hours


2 years old:

• the average baby got about 13.2 hours of total sleep

• 50% of babies got between 12.3 and 14 hours

• 96% of babies got between 10.8 and 15.6 hours

These numbers represent total sleep duration—-how much babies slept over a 24-hour period. Of course, not all of this sleep time occurred at night.

One-month-old babies slept an average of 8 hours each night, with 96% of babies getting between 6 and 13.3 hours of nighttime sleep. At 3 months, babies spent more time sleeping at night—-10 hours, on average. For babies over 6 months, the amount of nighttime sleep stayed fairly constant across ages—about 11 hours on average, with a range of approximately 9-13 hours (Iglowstein et al 2003).

Baby sleep requirements are also met by sleeping during the day. Here is some information on the amount of time babies spent taking naps.

Daytime sleep (naps)

In the Swiss study (Iglowstein et al 2003), all babies took naps throughout their first year. Most babies continued the practice of napping throughout their second year, with 87% of 2-year olds taking daytime naps. Time spent napping followed these patterns:

1 month old

• the average baby slept between 5 and 6 hours during the daytime

• 50% of babies slept between approximately 4.5 and 7 hours

• 96% of babies slept between 2 and 9 hours


3 months old

• the average baby slept a bit less than 5 hours during the daytime

• 50% of babies slept between approximately 3.5 and 6 hours

• 96% of babies slept between 1 and 8 hours

6 months old

• the average baby slept about 3.4 hours during the daytime

• 50% of babies slept between approximately 2.5 and 4.5 hours

• 96% of babies slept between 0.4 and 6.4 hours


9 months old

• the average baby slept about 2.8 hours during the daytime

• 50% of babies slept between approximately 2 and 4 hours

• 96% of babies slept between 0.2 and 5.3 hours


1 year old

• the average baby slept about 2.4 hours during the daytime

• 50% of babies slept between approximately 2 and 3.5 hours

• 96% of babies slept between 0.2 and 4.6 hours


18 months old

• the average baby slept about 2 hours during the daytime

• 50% of babies slept between approximately 1.5 to 2.5 hours

• 96% of babies slept between 0.5 and 3.6 hours


2 years old

• the average baby slept about 1.8 hours during the daytime

• 50% of babies slept between approximately 1.3 to 2.3 hours

• 96% of babies slept between 0.7 and 2.9 hours


Elsewhere, naps may be on the decline. In a recent study of American children, 82% of babies over 18 months were not taking any naps on some or all days (Acebo et al 2005).

Baby sleep requirements: Why your baby may differ from the average

The statistics presented above represent some of the best research we have on average sleep times for children. But before you try to apply them to your own baby, keep in mind that the study focused on a specific population: Swiss kids born between 1974 and 1993.

Depending on cultural factors and individual differences, baby sleep patterns might differ significantly from those of the Swiss study population.

Consider these points:

Sleep times vary cross-culturally. In one study, sixteen-week old Kokwet babies—members of the Kipsigi ethnic group in Kenya—slept about 2 hours less per 24 hours than did American babies of the same age (Super and Harkness 1982; Parmalee et al 1964). In another study, 3-month old Dutch infants slept 2 hours more than American infants did (Super et al 1996). Such cultural differences in sleep duration may reflect important differences in the ways that babies are handled and fed during the day. For instance, American parents believe it is especially important to provide their babies with lots of sensory stimulation. Dutch parents are more likely to emphasize rest and regularity (Super et al 1996).

Breastfed babies tend to sleep less. Studies of 4 week-old infants found that breastfed babies got less sleep than did formula-fed babies (Quillin and Glenn 2004; Quillin 1997).

Cosleeping babies sleep less. A Swiss study has reported that children over 9 months of age who shared their parents’ beds slept less than did children who slept alone (Jenni et al 2005).

Each baby is different. As the data above indicate, babies may vary greatly in the amount of time that they sleep. And recent research suggests that some variation in individual sleep patterns has a biological basis. Adults subjected to identical sleep conditions respond in individualistic ways—even when they all belong to the same culture (Tucker et al 2007). Recent genetic research indicates that some aspects of sleep—-including sleep duration—-have a genetic basis (Gottlieb et al 2007). Baby sleep requirements may therefore “run in the family.”

Coping with the individualized nature of baby sleep requirements

The charts above offer clues to your infant’s sleep needs. But for a more fine-tuned estimate of baby sleep requirements, you need to consider your baby’s behavior. You can learn a lot by observing what time(s) of day she seems sleepy and what her behavior is like when she wakes up in the morning.

But babies can be hard to read. For help identifying when your baby is tired--and identifying his personal baby sleep requirements--see this guide to signs of sleep deprivation in babies and children.



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Last modified 5/08